“Nobody has any idea how many police shootings there are,” said Robert Weisberg, a Stanford Law School professor and co-director of the Stanford Criminal Justice Center. “Any scrutiny is good, and if this causes more scrutiny, that’s good, and if it causes any embarrassment, that’s fine.”

The Texas State study said San Francisco police did not report any of their six fatal shootings to the state last year, including the December killing of Mario Woods, which sparked a federal review of the city’s force.

The researchers found two additional cases, in 2008 and 2010, in which a San Francisco police killing did not end up being recorded by the state. There was no indication, they said, that the discrepancies were purposeful...The study reveals the degree to which California is part of an undercounting problem so widespread that two news organizations — the Washington Post and Guardian US — opted to perform their own counts of police killings last year, after figures released by the FBI were discredited as incomplete.

The results marked the first time the American public was given a reasonably full — though still imperfect — picture of officer-involved killings. The Post counted 991 fatal police shootings in the U.S. in 2015 and 189 in California, a number similar to the one calculated by Texas State University.

Scrutiny of such statistics was part of the aftermath of the Aug. 9, 2014, death of Michael Brown, an unarmed 18-year-old black man who was shot and killed by a white police officer in Ferguson, Mo.

Since then, a number of video-recorded police killings — including that of [Mario]Woods in San Francisco — have ignited calls for reforms to reduce the bloodshed...